Noobie (1 Viewer)

I come hat in hand for any advice and direction you might give me. I know little or nothing about using a telescope for digiscoping but have the following old telescope

Meade ETX series (no specific model marked on the bottom)
D=90mm F=1250 f/13.8

Just picked up a Canon A590 on clearance sale

I've tried searching within this forum for any direction on the use of this telescope with any camera (I also own a Nikon D70) or specifically with the A590 but haven't had any luck.

Any direction on just getting the necessary components to couple them together would be very much appreciated.

OK, during the period of deafening silence I've been doing some "googling" and found the ScopeTronix web site. They appear to have a lot of "adapters" for both "afocal" and "prime focus"(I think I got the terms correct) techniques. But their "wizard" seems out of date. Didn't have at least one of my cameras listed and the only phone number for them that I could find was no longer in service. It was buried in the "wizard", otherwise on their contact page there were no phone numbers. Great if you know what you're doing but not so good if your a noobie and have questions.

So anyone have any experience doing business with ScopeTronix?

Yeah, sorry for no replies. I was writing you a reply a couple of days ago but something came up and I had to dash out. Kids are on school holidays too so not had much time to sit at the PC.

One option is to use the Digi-Kit from CNC Supply and this allows you to fit a camera like the A590 to any suitable astro eyepiece such as those on the list they provide. Go to http://www.cncsupplyinc.com/ and look under the Digi Kit Digital Camera Adapters. At the top of the page it lists suitable eyepieces under the bit where it says Note. Then scroll down to find your camera model. Their adapter fits onto the eyepiece where the rubber eyecup is. You take off the eyecup and on some eyepieces like the ones they list there should be a groove to hold the eyecup in place. Their adapter has three little screws that screw into this groove and hold the adapter in position. Pretty sure that part of the kit is also the tube that fits onto the camera which allows everything to be screwed together. Prices aren't that cheap but they make quality gear.

Another option is to use the Canon LA-DC52G Lens Adapter and screw this to any eyepiece that has threads under the rubber eyecup to allow this. As far as I can remember there is a small button near where the lens comes out on the Canon and when pressed it releases the ring around the lens. This is where the adapter fits on, I think it's some sort of bayonet fitting. This provides you with a 52mm thread to then screw onto any accommodating eyepiece and depending on the thread size a simple step down ring will usually get you to the right thread size. Eyepieces with threads on that I know of are the Baader Hyperion series and the Williams Optics DCL-28 but this method isn't as flexible as the first option as the eyepieces in the first option are cheaper.

Third option is to just use some sort of universal digiscoping adapter of which there are various types such as fixed ones and the type that swing out of the way.

I haven't used Scopetronix myself. I think they went bust a while back and then started up again but not sure of all the details.

Post a reply on which route you think is best and see if any more ideas come up.

Edit - also the CNC Supply website has some specialized ETX accessories under a separate section that you may be interested in. Can be accessed from their home page.

Paul.

Paul, thanks for the reply and direction to CNC. I picked up an adapter for my new A590 that you talked about, to get me to 52mm on eBay. That arrived a couple of days ago. So I'm going to look at the CNC site and see if I can make some sense of it all. I think that I should try a "afocal" solution with the A590 first and then maybe look into a "Prime Focus" solution with my Nikon D70 in the future if the "digiscoping" bug really bites me. Silly me, acting like I know what I'm talking about.

Thanks again for the direction and I'll get back with you as soon as I read enough to even know what questions to ask. :t:

I think I'm going the right direction

Paul, after studing the CNC web site and emails to them, it looks like I need the "1.5" Universal T Adapter, item# UT1 and the "52mm to T Step Ring, item # SR52T". For some reason my Meade MA25mm eye piece doesn't have a threaded end and so I have to use the universal adapter.

But more importantly I can also get a "Rear Port Adapter for ETX & C90/NexStar 4 item# ETXVB". Which is described as

"The 1.25" Rear Port Adapter threads onto the rear port of any ETX-90/105/125 or C90/NexStar 4 and allows you to view or image straight through the scope. This unit has a standard 1.25" eyepiece port on the back end."

Is there any difference in optical function by looking through an MA25mm eye piece in the top port or the rear port?

I thought that folks typically used the "rear port" for "prime focus" in which you would take a lensess camera like a DSLR and with some kind of T-mount and attach the camera directly to the back of the telescope. But without an eye piece and without the camera's own primary lens.

Thanks for any and all clarification you can give me on these differences.

With an eyepiece the image needs to be turned the correct way up and this is done with a prism. This is why the eyepiece goes in the top port as this route takes the image through a prism. The rear port doesn't use a prism and this is why it's used for prime focus as the image is upside down but this is the correct way up for prime focus photography. If you are using a dslr without a lens then go through the rear and for anything else that needs an eyepiece then go through the top port.

Paul.

Paul Corfield said:

With an eyepiece the image needs to be turned the correct way up and this is done with a prism. This is why the eyepiece goes in the top port as this route takes the image through a prism. The rear port doesn't use a prism and this is why it's used for prime focus as the image is upside down but this is the correct way up for prime focus photography. If you are using a dslr without a lens then go through the rear and for anything else that needs an eyepiece then go through the top port.

Paul.

Click to expand...

Paul, thank you, as soon as I finish here I'm going to place the order. Looks like the only reason to use the rear port adapter with an eye piece would be if it was more convenient to have the camera physically mounted on the back instead of on top. Since you can very easily "flip" the resulting photo image with software later.. . . . . . . Now having said that out loud so to speak. . . that might be convenient at times to have the camera mounted on the rear if I'm shooting more horizontally then in the sky. I think I'll throw that on the order too just to have it to play with.

Thanks again for your clarifications. :t:

I know that I wouldn't have as flexible a solution as your telescope but I've had this telescope sitting on the shelf for years and so for less then $100 I'll get to do some experimenting with it. ||

Only thing with putting an eyepiece in the rear port is that you would need some extension tube between the scope and eyepiece to be able to reach focus. With the top port this isn't needed because the prism acts as the extension to the light path. Standard 1.25" diameter extension tubes are generally available in 35mm, 50mm and 80mm lengths. Not sure how much you would need to reach focus but you could experiment with an eyepiece just held behind the scope.

Paul.

Paul Corfield said:

Only thing with putting an eyepiece in the rear port is that you would need some extension tube between the scope and eyepiece to be able to reach focus. With the top port this isn't needed because the prism acts as the extension to the light path. Standard 1.25" diameter extension tubes are generally available in 35mm, 50mm and 80mm lengths. Not sure how much you would need to reach focus but you could experiment with an eyepiece just held behind the scope.

Paul.

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Hopefully CNC's solution has taken that into consideration. I can't imagine that they would sell something that is described as such and then not work. I'll cross my fingers that it's a viable solution for me and that I haven't thrown away $35 for the adapter. Right now I can't even get the order to go through. Some kind of error between their secured cart services and PayPal I believe.

Just had a look on the CNC website and I see it has a 1.25" hole in the back for an eyepiece so it should be the correct length of extension.

Paul.

Paul, finally got the order placed and should have the adapters in a couple of days. Really excited to "play" with my telescope and camera combination. Thanks again for your helping me sort some of this out! With any luck at all I'll have some pictures to show shortly. :t:

Paul and to anyone else that's trying to get started into Digiscoping with a Meade ETX 90.

I got my couplers from CNC Supply in Florida yesterday and within 15 minutes had the Canon A590 camera mounted to the Meade telescope and ready to go. I ordered these for my telescope setup.

SR5T 52mm to T Step Ring
UT1 1.5 inch Universal T Adapter

I had to use the universal T Adapter because for some reason my 25mm eye piece did not have a threaded end. Also I already had the A590 ring adapter to get me to 52mm.

Camera and Telescope

Camera and Telescope

I set up the telescope on a stand in the back yard and decided to see how well I could see and photograph a radio tower that is about 1.4 miles/2.256km away. Not a great photo what with the heat waves distorting things and all but a quick visual to my non-technical family members of the magnification effect.


Normal view of the tower

Top of tower through telescope

This morning I was up and out early and saw the full moon and decided to set up the telescope and try to take a couple of pictures even though it was low on the horizon, about 25 degrees. The results were not something to win prizes with but I was happy with as my first attempt.

Moon 1

Moon 2


Also I must say that Robert with CNC Supply was very responsive to my emails and even though we were having problems getting the order through PayPal, Robert shipped what I needed very quickly and I had the couplers within days! I would definitely recommend him based on this experience.

I haven't played around with the rear port adapter yet. Maybe this weekend when I get some more time.

Now the real work of getting some experience setting up the camera for optimal pictures and cleaning the optics!

Next project is a better stand or tripod!

Thanks again Paul for your support and guidance! :t:

I used to use the ETX-90 for digiscoping and videoscoping. I used both the top and rear ports and noticed very little difference between them. I mostly used a 32mm Orion eyepiece to which I glued a 28mm step ring to fit my Coolpix 995 camera. The long focal length of this scope means you have to be very mindful of the total magnification. With a 25mm eyepiece you are getting 50X to start with before adding any camera zoom. Most digiscopers start around 20-30X mag on the scope. I have a Scopetronix 18mm WA and this is just too much power for my scope-camera combination. I found the Scopetronix 40mm Maxview works well with this scope. You really need good light with this scope to get shutter speeds sufficient to avoid vibrations. You can get some very nice photos with this scope as long as you are mindful of the limitations. Search my gallery for examples of photos taken with the ETX-90.

Good work so far and glad to see it all set up and working. Like Bluedubius says, a lower power eyepiece will yield better results, especially if sticking with 1.25" eyepieces. Stepping up to a 2" eyepiece can yield almost twice as much field of view which could equal twice as much light getting to the camera. Have a look at http://www.siebertoptics.com/SiebertOptics-eyepieceadapters.html down the right hand side of the screen for some useful info on ETX scopes. This would be a good website to source an eyepiece in the future. A lot better than most branded ones and certainly up with the likes of televue eyepieces for lower cost.

This website can also turn up some decent low priced eyepieces and I've ordered stuff from them in the past. Plenty of other optical goodies too if you are into all that stuff. http://www.surplusshed.com/pages/category/eyepiecessets_1.html

I'm away for a couple of weeks now, staying on a farm in the coutryside and taking the scope so shall look in on this tread when I get back.

Paul.

bluedubius said:

I used to use the ETX-90 for digiscoping and videoscoping. I used both the top and rear ports and noticed very little difference between them. I mostly used a 32mm Orion eyepiece to which I glued a 28mm step ring to fit my Coolpix 995 camera. The long focal length of this scope means you have to be very mindful of the total magnification. With a 25mm eyepiece you are getting 50X to start with before adding any camera zoom. Most digiscopers start around 20-30X mag on the scope. I have a Scopetronix 18mm WA and this is just too much power for my scope-camera combination. I found the Scopetronix 40mm Maxview works well with this scope. You really need good light with this scope to get shutter speeds sufficient to avoid vibrations. You can get some very nice photos with this scope as long as you are mindful of the limitations. Search my gallery for examples of photos taken with the ETX-90.

Click to expand...

Thank you for your input, I haven't had a lot of time to work with my new telescope and camera combination but as you've stated the 25mm eyepiece is a little too much magnification and I'm looking for a 32mm eyepiece to use instead.

Since you have specific experience with a Meade telescope I've got another noobie question. Apparently the eyepiece gives you the "magnification factor" for a Meade type telescope, what do you get when you attach a SLR camera via a "T-ring" to the rear port without a lens or an eyepiece?

Also I've been looking around for eyepieces and as an example I found an eyepiece described as "Meade 1.25" x 32mm 4-Element Plossl Telescope Eyepiece". Is a "Plossl" eyepiece a type of eyepiece or a Brand? This was on eBay for around $27. Is that a typical price for a quality eyepiece?

Thanks for all your help.

Roy

Paul Corfield said:

Good work so far and glad to see it all set up and working. Like Bluedubius says, a lower power eyepiece will yield better results, especially if sticking with 1.25" eyepieces. Stepping up to a 2" eyepiece can yield almost twice as much field of view which could equal twice as much light getting to the camera. Have a look at http://www.siebertoptics.com/SiebertOptics-eyepieceadapters.html down the right hand side of the screen for some useful info on ETX scopes. This would be a good website to source an eyepiece in the future. A lot better than most branded ones and certainly up with the likes of televue eyepieces for lower cost.

This website can also turn up some decent low priced eyepieces and I've ordered stuff from them in the past. Plenty of other optical goodies too if you are into all that stuff. http://www.surplusshed.com/pages/category/eyepiecessets_1.html

I'm away for a couple of weeks now, staying on a farm in the coutryside and taking the scope so shall look in on this tread when I get back.

Paul.

Click to expand...

Paul, thanks for the additional links and I hope that you enjoyed your stay at the farm. Sounds relaxing!

Roy,

Not sure of the "power" factor shooting without an eyepiece through the rear port, but the focal length is the same focal length as the telescope (1250mm for the ETX-90, plus there is usually a "crop factor" for the camera, which for my Nikon D2H or Fuji S2 Pro is 1.5x...or an equivalent of 1875mm).

In my experience, I have not done as well shooting straight through without an eyepiece using a DSLR on the ETX as I did with traditional digiscoping using an eyepiece and point and shoot digicam). I have older DSLR's that don't do as well at high ISO settings as the newer DSLR's like Paul's Canon. Higher ISO might mean better opportunities using higher shutter speeds which might mean better photos than I could get.

Also, I have better results using a DSLR and the Celestron 80ED refractor than I got with the ETX. If I were you and already had the ETX, I would at least try it and see what I could do. There is a photographer named Michael Downs that has posted a number of photos taken using different Mak/Cass scopes like the ETX and Orion brands in the gallery at Anacortes Telescope and Wild Bird website, and I think maybe a few here as well. Here is a link to a recent photo he posted there:

http://www.buytelescopes.com/viewphoto.aspx?pid=19673&sg=4

Good luck.

Rick

I just checked and Michael Downs has a number of photos in the gallery here and some of them are digiscoped using the Orion and ETX Mak/Cass scopes.

Here are two comparison shots. Both were taken in good light with a Fuji S2 Pro DSLR camera from the rear of the scope. One short extension tube used with the Celestron to bring the image to focus, and the Meade ETX-90 camera adapter (which is basically an extension tube that screws onto the rear port of the ETX). No eyepiece on the scopes or lens on the camera. Shots taken within minutes of each other from the same spot with the target leaves being about 20m away. I focused on a center leaf with a hole in it. Resized and levels only in PS 6.0 (no sharpening). Celestron is a 600mm f7.5 and the Meade ETX is a 1250mm f13.8. The Fuji has a 1.5x crop factor.

bluedubius, thanks for the photo comparison. I appreciate you taking the time and effort to set things up to take those pictures for me.

I've got a simple question that you might be able to answer for me. I'm having problems getting my Canon A590 to focus. I zoom in to fill the frame and then I try to get it to auto focus. I have to make repeated attempts to get the camera to finally think that it's happy with a focus. Any "tricks of the trade" to improving focusing. This camera also has a manual focus mode but so far I'm finding that because this camera has a lower resolution rear display that it's hard to tell when I'm in focus manually either.

Also I've ordered a 32mm eyepiece and should be getting that next week.